Carrier-to-interference plus noise ratio is a measure of the signal quality between two wireless communication devices, e.g., between a base station and a mobile (typically remote) station. There are two types of CINR: Physical CINR (pCINR) and Effective CINR (eCINR).
pCINR is the inherent measure of the signal quality. eCINR is an indication of the actual performance of the signal under real channel conditions, i.e., what order of modulation and encoding scheme can the channel support under real channel conditions. eCINR, and thus the MCS, depend both on the pCINR and the actual conditions of the wireless channel between the two devices.
eCINR is the ultimate measure of signal quality under prevailing channel conditions, and it dictates the actual modulation and encoding scheme when transmitting to a destination device under fading channel conditions. In accordance with the IEEE 802.16 wireless communication standard (known commercially as WiMAX™), a mobile station needs to compute the downlink signal eCINR and report it back to the base station. The base station then assigns a modulation and encoding scheme for downlink traffic to the mobile station accordingly. For uplink transmissions, the base station needs to compute the uplink traffic eCINR, and it assigns a modulation and encoding scheme to be used by the mobile station for uplink traffic accordingly. eCINR is thus a significant parameter used in link adaptation. As such, there is a need to properly obtain an appropriate value for eCINR.